Incandescent electric lamp



NMA (Mr, QSS. VAN ECK ET AL,

INCANDESCENT ELECTRIC LAMP Filed June l, 1932 Patented Nov. 14, 1933 PATENT OFFICE INCANDESCENT ELECTRIC LAlVIP Jacob van Eck and Fekko Fekkes, Rotterdam, Netherlands Application June 1, 1932. Serial No. 614,741

1 Claim.

The present invention consists in an incandescent electric lamp having, between the neck and the bulb, an annular reflecting portion arranged around the filament and having a concave or convex channel-shape, the surface of this portion being substantially that generated by the revolution of a parabola about the axis of the lamp. The bridge element supporting the filament is of ordinary well known construction and said ele- 1 ment may be provided with a reflecting disc cooperating With said annular reflecting portion obtained by gilding, silvering or otherwise. Said reflecting portion is applied outside or inside the glass of the lamp. The bulb of the lamp will pref- 16 erably have the shape of a truncated cone closed by a convex bottom, so as to secure a considerable inner volume in the lamp, for the purpose of keeping the inner temperature as low as possible and avoiding the detrimental effect of heat upon the reflecting portion.

The edges of said reflecting portion may be at right angles or inclined with respect to the axis of the bulb.

The invention will be described hereafter in two forms of embodiment, with refrence to the accompanying drawing, in which:

Figs. 1 and 2 are horizontal axial sections of lamps constructed in conformity with the inventlon.

30 Between the bulb l and the neck 2 is formed an annular channel-shaped reflecting band 3, either convex or concave, this portion surrounding the filament and the surface of this portion being substantially that generated by the revolution of a parabola around the axis of the lamp. This portion will be gilded or silvered or made reflectant in any other way, between the planes a-a, b-b or a-a", b-b, either externally or inwardly. The bridge element 4 supporting the filament 5, which is fed with current by the leads 6, will be of ordinary construction, but may be provided with a reflecting disc 7 fixed on the stem, between two rings of glass or the like soldered to said stem. The bulb l will have the shape illustrated, namely that of a truncated cone of straight section and having a convex bottom so as to secure an inner volume of considerable dimension, for the purpose of keeping the temperature within the lamp so reduced that no detrimental eiiect will occur upon the reflecting portion. The planes a-a, b-b, a"-a" and b'-b may be at right angles or inclined with respect to the axis of the bulb.

The incandescent electric lamp as described presents the advantage of securing a perfect diffusion and reflection of the light rays, so that the lighting of the illuminated surface effected by the lamp will be particularly strong.

It is obvious that the parabola form constituting the generatrix of the reflecting portion may be approximately parabolic and formed eventually by a succession of straight or curved sections.

We claim:

An incandescent electric lamp having between the neck and the bulb an annular channel-shaped reflecting portion arranged around the filament, the surface of this portion being substantially that generated by the revolution of a parabola about the axis of the lamp, the bulb having substantially the shape of a truncated cone closed by a convex bottom, and a plane reflecting disc mounted on the bridge element supporting the filament, the edge of said disc leavingan annular space between it and the neck wall, substantially o as described for the purpose set forth.

JACOB vAN ECK. FEKKO FEKKES. 

